Rail beds must often cross a roadway or a pedestrian walkway at grade level or be built within the same roadway. At such intersections and locations, the recessed areas of the rail bed are often built up so that the surface of the road or walkway is at the same level as the top surface of the rails, with the exception of the recesses provided adjacent to the rails to accommodate the rail car wheels.
To accomplish this type of shared right-of-way construction, the recessed areas on either side of the rails are often filled with road bed material, such as poured concrete. However, because the rails are often used as signal conductors or negative returns for the railcar's power traction, they must be substantially electrically isolated from the ground. Electrical isolation also functions to inhibit the corrosion of the rails and underground utilities. Rail boots and flangeway formers also provide vibration isolation to extend concrete life and to reduce noise generated by the trolleys.
For this reason, many transit systems use an extruded flangeway former in combination with a rail boot to improve the electrical isolation of the rail. This also eliminates the need to form a flangeway in the road surface. However, prior art systems do not effectively secure the flangeway formers in the proper position during installation while the concrete is poured and cured.
Once installed, there can be a tendency for the flangeway former to shift during installation due to pressure from the road bed material as the area around the flangeway and rail boot is filled. Conventional flangeways also have a tendency over time to pull away from the road bed material towards the rail following installation most commonly from dirt penetrating the seam between the road bed material and the flangeway former. Such shifting of the flangeway former reduces the width of the flangeway, resulting in damage to the flangeway former by rail wheels running in the flangeway. The flangeway former can also shrink along its length, resulting in gaps between adjacent lengths of flangeway material.